Rubbish pud (4)
I believe the answer is:
duff
This could be a double definition.
'rubbish' is the first definition.
Although both the answer and definition are singular nouns, I can't see how one could define the other.
'pud' is the second definition.
(duff is a kind of pud)
Can you help me to learn more?
(Other definitions for duff that I've seen before include "Steamed pudding - 2" , "False; steamed pudding" , "Unsuccessful" , "seat" , "Bad" .)